Graptopetalum paraguayense (GP) are medicinal plants that look like lotus (rosette). However, their leaves are drought resistant. Therefore, they are referred to as stone lotus or Cyperus alternifolius. They belong to Crassulaceae sinocrassula. They are perennial succulent plants. The plant is smooth and thick. The color is powdery white and the leaves aggregates on top of the stem; the leaves are without stems with an inverted egg shape arranged like a lotus flower (rosette), which gives it the name stone lotus. The plants occasionally bloom small white flowers in the spring and fall. GP may be cultivated for ornamental purposes or for medicinal use.
GP is considered to have potentially beneficial effects in alleviating hepatic disorders, lowering blood pressure, whitening skin, relieving pain and infections, inhibiting inflammation, and improving brain function.
GP is rich in ash materials and various nutrients, such as dietary fibers, sodium, calcium, potassium, magnesium, iron, vitamins C, B1, B2, B6, folic acid, nicotinic acid, and β-carotene. It is an edible plant. Its pharmacological activities include rejuvenation of liver cells, improving immune functions, alleviating fragile blood vessel and abnormal permeability, preventing various diseases, such as high blood pressure, arteriosclerosis, chronic hepatitis, and liver cirrhosis.
GP was investigated as food supplement for the control of lipid levels in people with hyperlipoidemia (J Sci Food Agric. 2011 May; 91(7):1230-5). In a clinical trial, 18 hyperlipoidemia subjects were given 100 g of fresh GP daily. After eight weeks, the test subjects were assessed for their serum indicators and blood analysis. The results show that GP uptake can substantially increase the antioxidant activities in the bodies (the levels of ascorbic acid and α-tocopherol in blood increased and the level of malondialdehyde decreased; glutathione concentration increased in red blood cells; glutathione peroxidase and catalase activities also increased). It was found that a product from ethyl acetate re-extraction of a 50% ethanol extract of GP has neuro-protective effects in rats with stroke (Am. J. Chin. Med., 2010, 38(3): 495-516).
Researchers in Taiwan also found that GP can inhibit hepatitis and hepatic fibrosis that is induced by dimethylnitrosamine (DMN) or carbon tetrachloride (CCl4). In in vitro cell studies of hepatic fibrosis, it was found: (1) GP-W could inhibit the growth of hepatic stellate cells (HSC) or induce their apoptosis; (2) GP extracts could delay the aging of Kupffer cells, as compared to a control group; (3) GP extracts could inhibit lipopolysaccharide (LPS)-induced inflammation in Kupffer cells, resulting in lower expression of TNF-α and IL-6.
GP active ingredients have been subjects of several patent applications, including TW patent application publication No. TW200616655 (Pharmaceutical use of Graptopetalum and related plants), which corresponds to U.S. Pat. No. 7,364,758; U.S. patent application Publication No. US 2012/259004 A1 (Anti-cancer extract and compounds); Taiwan patent application publication No. TW201219047 (Anti-cancer extract and compounds); and Chinese patent application publication No. CN103269706 (Anti-cancer extract and compounds).
In U.S. Pat. No. 7,364,758 (“Pharmaceutical use of Graptopetalum and related plants”), GP flower extracts were obtained using water, ethanol, acetone, methanol, or a mixture thereof as a solvent, while the Pharmaceutical use is for the treatment or prevention of a disease selected from the group consisting of liver inflammation, hepatic steatosis, liver fibrosis, hepatocirrhosis, and hepatitis B. The extracts disclosed in the '758 patent were obtained with polar solvents.
The patent applications “Anti-cancer extract and compounds” mainly concern DMSO extracts of Graptopetalum sp. Rhodiola sp. or Echeveria sp. In these applications, the DMSO extracts were further purified with Sephadex LH20 column chromatography to isolate HH-F3, a proanthocyanidin compound with a molecule weight of about 18 kD. However, the use of column chromatography makes it impractical to have large scale productions. In addition, column elution requires a large amount of organic solvents, and the necessary processes to concentrate the fractions are also costly.
While these prior art disclosures show that GP extracts have beneficial medicinal uses and the prior art methods can produce OP extracts with good activities, there is still a need for better methods for the preparation of GP extracts, particularly methods that are suitable for economical, large scale productions.